Sound generated from a loudspeaker built into a device capable of inputting and outputting voice may be received as an echo from a microphone built into the device. Voice uttered by a speaker other than a particular speaker may be captured together with voice of the particular speaker by the microphone. Such an echo and other speaker's voice are noise components contained in an input voice signal, which may degrade the quality of the input voice signal and reduce the intelligibility of the voice intended to be captured. In view of this, techniques have been proposed for adaptively suppressing such a noise component (for example, see Japanese Laid-open Patent Publication No. 2009-94802 and Japanese Laid-open Patent Publication No. 2005-84244).